Abstract
A practical zinc-MsOH mediated intra-molecular reductive cyclisation and its application in the synthesis of tafamidis is presented starting from the readily available 3-hydroxy-4-nitrobenzoic acid as a precursor. The key reductive cyclization step involves the use of a combination of the readily available zinc and MsOH as the catalyst system. This methodology provides an attractive route to 2-aryl benzoxazoles from ortho-nitro phenols under mild reaction conditions. This methodology is developed on a multi-gram scale and without the need for column chromatography.
Graphic abstract
A new and alternative zinc-MsOH mediated intra-molecular reductive cyclisation and its application in the synthesis of tafamidis is reported starting from the readily available 3-hydroxy-4-nitrobenzoic acid as precursor. This method provides an attractive route to 2-aryl benzoxazoles from ortho-nitro phenols under mild reaction conditions.
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The authors gratefully acknowledge Aurobindo Pharma Limited for the generous support to publish this work. The authors are also thankful to the Chemical Research Department and Analytical Research Department for the support and co-operation.
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Karumanchi, K., Natarajan, S.K., Gadde, S. et al. A new synthesis of tafamidis via zinc-MsOH mediated reductive cyclisation strategy. J Chem Sci 133, 48 (2021). https://doi.org/10.1007/s12039-021-01910-9
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DOI: https://doi.org/10.1007/s12039-021-01910-9